Adhesive transfers



Sept 26, 1967 T, J. EN'GELBACH 3,343,978

ADHESIVE TRANSFERS Filed Jan. 9, 1964 2 Sheets-Sheet-2 INVENTOK F/o MnsJ CA/@EL @Ac/f BY MW United States Patent O 3,343,978 ADHESIVE TRANSFERSThomas I. Engelbach, Middletown, NJ., assignor to Avery ProductsCorporation, San Marino, Calif., a corporation of California Filed Jan.9, 1964, Ser. No. 339,062 7 Claims. (Cl. 117-76) This application is acontinuation-in-part of the copendiug application of Thomas I.Engelbach, S.N. 99,244, iiled Mar. 29, 1961, now abandoned.

This invention relates to adhesive transfers and more particularly, toadhesive transfers, processes for producing them, and methods ofapplying them to other surfaces.

An object of this invention is to transfer a pressuresensitive adhesiveto a body so that the face surface thereof after transfer is adapted toadhere to another body upon the application of pressure to join togetherfirmly the two bodies.

Another object of this invention is to afliX an adhesive to a portion ofan article by the application of heat or solvent whereby other surfacesmay be bound to the article at such portion.

Another object of this invention is to bind two surfaces of differentmaterials for which a common adhesive material is not available.

A further object of this invention is to provide a label which can besealed to a package and can be pulled free to expose a tacky surfacewhich can be employed to reseal the package.

An example of the need of an efficient, economical jointure isillustrated by the so-called bumper label. The customary procedure formanufacturing these labels is for a job printer to purchase blank stripsof paper having at the two ends thereof tacky adhesives completelycovered with a release paper. He then prints the desired message ordesign on the strip. The bumper strip is adhered to the automobilebumper by removing the release paper and applying pressure to the bumperstrip.

Currently used bumper strips frequently are covered only on portions ofthe obverse side and such strips, because of the non-uniformity ofsurface, are diliicult to print. In addition, the printer cannot use hisusual stock of paper for bumper labels but must procure special and morecostly adhesive bearing blanks for this purpose.

In accordance with one aspect of this invention, an adhesive transfer isprovided which can be applied to a label printed on any stock paper. Theprinter may proceed with the printing of the label in the same manner ashe would for any other type of printing and then apply the adhesivetransfer of this invention to the entire back or any desired portions ofthe back, such as the ends of the label.

In accordance with another aspect of this invention, an adhesivetransfer is provided which has a label eX- posed on a surface oppositethat containing an adhesive. The adhesive surface opposite thatcontaining the label may be activated by heat or solvent and afteractivation the transfer may be applied as a closure to a package. Thelabel can be pulled free exposing a tacky pressure sensitive adhesiveattached directly to the label sheet and capable of adhering to resealthe package. The adhesive transfer in accordance with this aspect of theinvention enables the closure of a package and its opening and resealingat any predetermined intervals.

The adhesive structures of this invention comprise a flexible substrate,a pressure sensitive adhesive in contact with the substrate, and anon-tacky layer adhering to the surface of the pressure sensitiveadhesive. The non-tacky layer may be heat activated, solvent activatedor both and is convertible to a tacky adhesive surface by the ap-3,343,978 Patented Sept. 26, 1967 ICC plication of heat or solvent. Whenthe pressure sensitive adhesive has greater cohesion than its adhesionto the substrate, the non-tacky layer of the adhesive structure whenactivated has at least 10% greater adhesiveness to the pressuresensitive adhesive than its cohesion. When the pressure sensitiveadhesive has greater adhesion to the substrate than its cohesion, thenon-tacky layer when activated has at least 10% greater cohesion thanits adhesion to the pressure sensitive adhesive.

In the first aspect of this invention, the pressure sensitive adhesiveof the adhesive structures of this invention has greater cohesion thanits adhesion to the substrate and the non-tacky layer of the adhesivestructure when activated has at least 10% greater adhesiveness to thepressure sensitive adhesive than its cohesion. The adhesive structuresor transfers in accordance with the first aspect of this invention areparticularly applicable to bumper labels and many and varied othersituations when the pressure sensitive adhesive has greater cohesionthan its adhesion to the substrate. Desirably, the characteristics ofthe substrate in this first aspect of applicants invention preferablyhas low adhesion to the pressure sensitive adhesive. The adhesivestructure in accordance with the first aspect of this invention istransferred to a surface by converting the non-tacky layer to a tackysurface by the application of heat in the case of a heat activatednon-tacky layer or by the application of solvent in the case of asolvent activated non-tacky layer and applying the resulting coatedtacky layer to the surface upon which the transfer is to be made.Pressure is then applied to the substrate to form a bond between theadhesive structure and the surface. The substrate is then removed toexpose the pressure sensitive adhesive for attachment to another surfacewhereby a jointure is effected between the two surfaces.

In the second aspect of this invention, the pressure sensitive adhesiveof the adhesive structure has greater adhesion to the substrate than itscohesion and the nontacky layer when activated has at least 10% greatercohesion than its adhesion to the pressure sensitive adhesive. Theadhesive structure in accordance with the second aspect of the inventionmay beA utilized as a means of closing packages. In this aspect of theinvention, the non-tacky layer is activated by heat or solvent and theactivated lsurface is applied to the portion of the package 'to beclosed. The substrate which comprises the opposite surface to that ofthe heat or solvent activated surface may have printing or advertising`or other designation thereon. If desired at any time after closure, theseal may be removed by grasping an end of the substrate. When the end ofthe substrate is elevated above the previously sealed part of thepackage, it carries with it the pressure sensitive adhesive because thepressure sensitive adhesive has greater adhesiveness to the substratethan its cohesion. The activated non-tacky layer remains on the -packagewrappings because when so activated it has 10% greater cohesion than itsadhesion to the pressure sensitive adhesive. When t-he end of thesubstrate is elevated above the previously sealed part of the package,therefore, a relatively clear cut break occurs between the pressuresensitive adhesive and the activated non-tacky layer. When it is desiredto reseal the substrate to the Wrappings, the tacky surface of thepressure sensitive adhesive on the substrate is contacted with the tackysurface of the activated non-tacky layer on the wrappings and thesubstrate and contacting wrappings are quickly rejoined by theapplication of pressure to form a com-plete closure member. Thisbreaking away and resealing may be repeated substantially indefinitelyas desired. This adhesive structure of this invention is particularlyadapted to the sealing of cellophane or Saran Wrapping of bread orsimilar food products. At the end of each cellophane or saran wrappedloaf of bread, for example, the cellophane or saran wrapping may befolded and the adhesive struct-ure attached thereto by the activation ofthe non-tacky layer. Printing or other advertising designations may beimprinted on the substrate prior to activation of the adhesive transfer.After activation of the non-tacky layer by solvent or heat, the labelseal may be ixedly attached to the folded portion of the bread wrapper.If desired, at any time thereafter, the substrate of the adhesive)transfer may be easily removed by simply lifting the substrate awayfrom the package. When so removed, the pressure sensitive adhesive isretained on the substrate and the activated non-tacky layer is retainedon the package. The pressure sensitive adhesive on the substrate and theactivated nontacky layer on the package insure a quick and effectiveseal when closure of the package of bread is again desired.

The non-tacky adhesive layer may be heat activated or solvent activated,or both, and is of a type such that the activation results in theconversion of the non-tacky adhesive into a tacky body having at leastgreater adhesiveness to the pressure sensitive adhesive than itscohesion or at least 10% greater cohesion than its adhesion to thepressure sensitive adhesive depending upon the particular adhesivestructure desired.

The non-tacky adhesive layer may be coated directly on Ito the pressuresensitive adhesive. Alternatively, it may lbe a strip or sheet ofmaterial, such as cellophane, adjacent the pressure sensitive adhesive.`When the non-tacky layer has at least 10% greater adhesiveness to thepressure sensitive adhesive than its cohesion, the pressure sensitiveadhesive has greater cohesion than its adhesion to the substrate. On theother hand, when the non-tacky layer has at least 10% greater cohesionthan its adhesion to the pressure sensitive adhesive, the pressuresensitive adhesive has greater adhesion to the substrate than itscohesion.

The substrate which may be of fibrous or non-fibrous structure or bothis a exible membrane. Examples of such a substrate are paper, plasticfilms, textiles, Holland cloth or cellophane.

In the production of the adhesive structure in which the pressuresensitive adhesive has greater cohesion than adhesion to the substrate,the substrate is desirably a flexible material which may be fibrous ornon-fibrous or a combination of both. Examples of a substrate for thispurpose are: paper, plastic films, textiles, Holland cloth, cellophaneor any other flexible material which by its characteristic or treatmenthas a lower adhesion for the pressurel sensitive adhesive.

For the production of an adhesive structure in Which the pressuresensitive adhesive has greater cohesion than adhesion to the substrateand in which the non-tacky layer has at least 10% greater adhesion tothe pressure sensitive adhesive than its cohesion, the non-tacky layermay be solvent activated or heat activated or both and in addition maybe thermosetting. The pressure sensitive adhesives may be reinforcedwith fiberglass or similar substances such as nylon lilament. Examplesof adhesives employed in this aspect of the invention are: hot meltadhesives, lacquers (solvent solution), dispersions (resin ground inwater) and emulsions of resins. For example, certain thermoplasticmaterials, such as polyvinyl acetate, may be simply melted and applied(hot melt). Alternatively, the polyvinyl acetate may be dissolved in asolvent such as tol-nene and applied as one of the adhesives. Again, thepolyvinyl acetate may be dispersed in -water by simply initiallygrinding 'the polyvinyl acetate -to fine particle size and agitating it`Finally, the polyvinyl acetate may be emulsied by any of the Well knownprocedures and the emulsion applied to obtain the desired coating. Thethermosetting resins may be utilized in the form of a lacquer orsolution or in the form of an emulsion to obtain the adhesive transferand the curing may be effected after the transfer has been applied tothe surfaces to be joined. A -solvent activated adhesive may be hotmelted or applied in the form 0f an emulsion to obtain the adhesivetransfer. The solvent is then removed by evaporation and the transferlater activated by a solvent when it is applied to the surface to bejoined. If the solvent activated adhesive is also thermosetting, thecuring is effected after the adhesive transfer is applied to thesurfaces 'to be joined.

In the production of an adhesive structure in which the pressuresensitive adhesive has greater adhesion than cohesion to the substrateand in which the non-tacky layer has at least 10% greater cohesion thanits adhesion to the pressure sensitive adhesive, the non-tacky layer maybe a coating or film, the properties of which depend on the type ofsurface to which it must adhere. For example, the non-tacky layer maycomprise cellophane as a carrier with a release coating on one side (incontact with the pressure sensitive adhesive) and a nitro cellulose orsaran layer on the other side, depending upon the surface to which it isto be bonded. Examples of surfaces are: nitrocellulose coatedcellophane, saran coated cellophane, polyethylene, orientedpolypropylene and paper. Polyethylene or polypropylene may be used as acarrier. If the nontacky layer is a coating, it may be for example,polyvinylidene chloride copolymer resin, of vinylidene chloridecopolymerized with about 5% of methylacrylate, itaconic acid oracryonitrile. One such composition is sold under the tradename of Dewey& Almys Daran 210. The substrate is desirably flexible and has greaterinternal strength than the adhesiveness of the pressure sensitiveadhesive. If used as a label, it would allow the label to be peeled backwithout tearing. Examples of label stock papers which may be used forthis purpose are: cast coated printing stock, litho label stock, olf-setlabel stock and machine finished label stock.

The pressure sensitive adhesive may be any pressure sensitive adhesivewhich has greater adhesiveness to the substrate than its cohesion.Examples of pressure sensitive adhesives are those later described anddesignated as formulations 2 and 3.

A more comprehensive understanding of this invention is obtained byreference to the accompanying drawing in which:

FIG. 1 is a perspective view partly broken away, of an adhesivestructure of this invention;

FIG. 2 is a side elevation of an adhesive shown in FIG. 1 andillustrates the manner of removing the substrate from an adhesive of thetype of adhesive structure in which the pressure sensitive adhesivethereof has greater cohesion than its adhesion to the substrate and inwhich the non-tacky layer thereof when activated has at least 10%greater adhesiveness to the pressure sensitive adhesive than itscohesion;

FIG. 2A is an adhesive structure shown in FIG. 1 and illustrates themanner of removing a label from an adhesive of the type of adhesivestructure in which the pressure sensitive adhesive thereof has greateradhesion to the substrate than its cohesion and in which the nontackylayer thereof when activated has at least 10% lgreater cohesion than itsadhesion to the pressure sensitive adhesive;

FIGS. 3 and 4 illustrate processes for the production of the adhesivetransfers of this invention;

FIGS. 5 and 6 show methods of laminating the adhesive transfer of thisinvention in a continuous manner to webs of flexible materials.

In FIGS. 1 and 2, the adhesive structure comprises a substrate 10,having a tacky pressure sensitive adhesive 11 in contact with a surfaceof the substrate. Intimately bound with and covering the pressuresensitive adhesive 11 is a layer 12 which is normally non-tacky and maybe a film or coating on the surface of the pressure sensitive adhesive.The non-tacky layer 12 is capable of being activated by heat or by asolvent to produce a tacky body.

The physical structure of the adhesive structure and the specialrelationship of the substrate, pressure adhesive and non-tacky layer isthe same whether the pressure sensitive adhesive has greater or lessadhesion to the substrate than its cohesion. If the pressure sensitiveadhesive has less adhesion to the substrate than its cohesion, thenon-tacky layer of the adhesive structure has at least greateradhesiveness to the pressure sensitive than its cohesion. On the otherhand, if the pressure sensitive adhesive has greater adhesion to thesubstrate than its cohesion, the non-tacky layer has at least 10%greater cohesion than its adhesiveness to the pressure sensitiveadhesive. Although the two different adhesive structures havesignificantly different characteristics, they may be manufactured by thesame techniques, as presently described, with the appropriate selectionof types of the three components, substrate, pressure adhesive andnontacky layer, to produce the particular kind of adhesive structuredesired.

An example of a non-tacky layer is a combination of neoprene and aphenol formaldehyde resin in a solvent such as toluene, xylene oracetone. Based on 100 parts of neoprene, there is mixed between 10 and50 parts by weight of phenol formaldehyde resin. Sufficient solvent isadded to permit easy distribution of the combination on the firstadhesive. Alternatively, a straight resin such as urea formaldehydedissolved in a solvent may be employed. Neoprene formulations are eithersolvent activated or heat activated. If solvent activated, a solventsuch as toluene is simply smeared or sprayed over the second adhesive,resulting in the formation of a tacky mass.

The application of the adhesive transfers of this invention isillustrated in FIGS. 2 and 2A. The second adhesive of the transfer isfirst activated by a solvent or by heat, depending upon itscharacteristics. For example, in the case of a neoprene type of solventactivated nontacky adhesive, a solvent such as benzene is smeared orsprayed over the neoprene adhesive and it becomes tacky. The tackyfacing of the activated previously non-tacky adhesive 12 is then appliedto the surface of an article 13 to be joined with the surface of anotherarticle. Pressure is applied through the substrate 10, as indicated bythe arrows, to insure binding of the adhesive transfer to the surface ofthe article 13. The substrate 10 is then removed, exposing the tackysurface of the first adhesive 11. That tacky surface then contacts thesurface of the second article to be joined. Pressure is applied toeffect good adhesion between the article 13 and the other article to bejoined to it.

FIGS. 3 and 4 show two methods for producing the adhesive transfers ofthis invention. In FIG. 3 a roll coating apparatus is employed, while inFIG. 4 roll and snray equipment is used.

In FIG. 3 a backing web or substrate 30 in the form of a coil 31 isunwound in the direction of the arrow and passes over a roller 32, undera coating head comprising two rollers 33 and 34 and a reservoir 35containing the first or pressure sensitive adhesive. The web with thefirst adhesive thereon is then passed through a drier 36 as indicated bythe direction of the arrow. After drying of the first adhesive, thecoated web passes over a roller 42, under a second coating headcomprising the rollers 37 and 38 and reservoir 39 containing the secondor non-tacky adhesive. It is then dried by passage through an oven 40.The coated web with the rst and second adhesives thereon is then woundup in the form of a coil 41.

In FIG. 4 the first or pressure sensitive adhesive is coated on a web inthe same manner as that illustrated in the apparatus shown in FIG. 3.The uncoated web 44 in the form of a coil 45 passes over a roller 46 andunder a coating head comprising a reservoir 47 containing the firstadhesive and two rollers 53 and 54. The coated web 44 then passesthrough a drier 48, after which a spray coating device 49 containing thesecond or non-tacky adhesive effects the coating of the second adhesiveover the 6 first adhesive on the web. The coated web then passes througha drier 50, over a roller 51, and the completely coated web is thencollected in the form of a coil 52.

In the practice of producing the adhesive transfers of this inventionwith the apparatus shown in FIGS. 3 and 4, the solvent for the secondadhesive desirably may be for the same purposes capable of swelling thefirst adhesive. In this way the first adhesive becomes intimately boundto the second adhesive.

FIG. 5 shows the method of laminating an adhesive transfer of FIG. 2 ofthis invention to a web of flexible material. A roll .60 of an adhesivetransfer 61 of this invention, the exposed or second adhesive of whichis normally non-tacky but capable of being activated by heat, passesover guide rollers 62 and 63 to a heat lamination station comprisingheated rollers 64 and 65. The rollers 64 and 65 may be heated by anyconvenient means such as by electricity or steam to maintain the rollersat a temperature sufficiently high rto activate the exposed or secondadhesive of the adhesive transfer 61. At the heat lamination station,the adhesive transfer is contacted with a flexible web 66 which issupplied by a supply roller 67 passing over a guide roller 68. Theheated rollers 64 and 65 rotate at a sufficient speed and exertsufficient pressure on the web 66 and adhesive transfer 61 to effectgood adhesion between the transfer and the web. The resulting laminationpasses over a guide roller 69 to be wound in the form of a roll 70.

FIG. 6 illustrates the method of laminating a web of an adhesivetransfer of FIG. 2 of this invention in which the exposed or secondadhesive is solvent activated. In FIG. 6, a roll 73 of an adhesivetransfer 74 of this invention in which the second or exposed adhesive isnormally non-tacky but capable of being activated by the application ofsolvent thereto, passes over guide rollers 75and 76 to a solvent spray77. The application of the -solvent on the exposed or second adhesiveactivates it. In the activated state, the second adhesive contacts a webof exible material 78 which is supplied from a roll 79 of the materialafter passage over a guide roller 80. The web 78 and the activatedsecond adhesive of the transfer 74 contact each other as they passbetween the two pressure rollers 81 and 82. The pressure exerted betweenthe rollers 81 and 82 and the speed of the passage of the web andtransfer are such that good adhesion is effected between the web andtransfer. The resulting lamination of web and transfer passes over aguide roller S3 to be wound in the form of a roll 84. The laminatingmethods illustrated by the apparatus of FIGS. 5 and 6 may also beemployed for producing laminated structures as shown in FIG. 2A.Examples of formulations which may be used as the adhesives of thisinvention are:

FORMULATION 1 Prelrsure sensitive adhesive with natural rubber las thebase material Parts by weightV Milled smoke sheet rubber Polyterpeneresin with a softening point of about 100 C. (Piccolyte 100 manufacturedby Pennsylvania Industrial Chemical Corporation is a polyter-FORMULATION 3 Pressm-e sensitive adhesive with polyzlroburylene as thebase material Parts by weight Polyisobutylene having a molecular weightwithin the range of 85-100,000 100 Polybutylene having a molecularweight within the range of 10-l2,000 Polyterpene resin having asoftening point of 100 C. (Piccolyte 100 is satisfactory 'for thispurpose.) 12.5 Toluene 325 FORMULATION 4 Pressure sensitive thermosettngadhesive Parts by weight Milled smoke sheet rubber 100 Polyterpene resinwith softening point of about 100 C. (Piccolyte 100 is satisfactory forthis purpose.) 125 Heat reactive phenolforrnaldehyde resin such asbakelite No. 10,282 which is manufactured by the Bakelite Division of-Union Carbide and Carbon Company 65 An antioxidant such asdi--naphthyl-para-phenyldieneiamine 3 Toluene 600 FORMULATION 5 Heatactivated adhesive Parts by weight Polyethylene having a molecularweight of Aabout Parts by weight Polyamid resin (Versamid 94,manufactured by General Mills Corporation is satisfactory for thispurpose.) Hydroabietyl alcohol (The hydroabietyl alcohol manufactured byHercules Powder Co. and sold under the name Abitol is satisfactory forthis purpose.) 7 Polyterpene resin with a softening Apoint of about 100C. (Piccolyte 100 may be used.) 20 Antiblock agent, s-uch as C-arnaubawax 10 FORMULATION 7 Solvent activated thermosetting adhesive Parts byweight Rapid crystallizing chloroprene polymer (Neoprene AC issatisfactory for this purpose.) 100 Zinc oxide 10 Heat reactingphenylformaldehy-de resin such as BAKELITE 10,282 manufactured by theBakelite Div. of Union Carbide & Carbon Co. 30 An antioxidant such asphenyl--naphthylamine 3 Toluene i 300 t3 FoRMULATioN s Solvent activatedadhesive which may be used as a norttacky coating Parts by Weight Anethylene vinyl acetate copolymer having a softening point of 243 F. (R &B) sold under trade name of Elvox 150 and manufactured by the E. I.

du Pont Co. 40 Paran having a melting point of 135 C 40 Polyterpeneresin with a melting point of C.

(Piccolyte 100 manufactured by Pennsylvania Industrial ChemicalCorporation is a polyterpene which is satisfactory for this purpose.)-20 Formulations l through 4 are suitable as the first adhesive, whileFormulations 5 and 6 are adapted for use as the second adhesive.Formulation 7 may be used as a rst or second adhesive.

The specific embodiments of the invention disclosed herein are not to beconstrued as limitations but as illustrations of the invention. Variouschanges and modifications may be made in carrying out this inventionwithout departing from the spirit and scope thereof.

A pressure sensitive adhesive is meant whenever the term first adhesiveis stated herein and a non-tacky solvent or heat activated adhesive ismeant whenever the term second adhesive is stated herein.

What is claimed is:

1. An adhesive structure comprising a flexible substrate layer, anon-tacky layer7 a pressure-sensitive adhesive having 'a first side inadhering contact with said substrate layer and a second side oppositesaid first side in Iadhering Contact with said non-tacky layer, saidnon-tacky layer being convertible to a layer having a tacky adhesivesurface on its side opposite said pressure-sensitive adhesive, theadhesion at one of said surfaces of said pressuresensitive adhesivebetween said pressure-sensitive adhesive and the adjacent one of saidlayers being less than the ad- Ihesion at the other of said surfaces ofsaid pressuresensitive adhesive between said pressure-sensitive adhesiveand the other one of said layers, said pressure-sensitive adhesiveseparating along said one surface thereof from the adjacent -layer landremaining with said other adjacent layer when said layers are pulledapart.

2. An adhesive structure as set forth in claim 1 wherein said non-tackylayer is a heat activated layer which is convertible to supply saidtacky adhesive surface by the application of heat.

3. An adhesive structure as set forth in claim 1 wherein said non-tackylayer is a solvent activated layer which is convertible to provide saidtacky adhesive surface by the application of a solvent.

4. An adhesive structure as set forth in claim 1 wherein said non-tackylayer after being converted to provide a tacky surface is `adapted toladhere to a surface of a body with an adherence sufficiently great toretain said nontacky layer with said surface of said body when saidsubstrate is pulled away from said body.

5. An adhesive structure as set forth in claim 1 wherein the adherencebetween the surface of said pressure sensitive adhesive and saidsubstrate is less than the adherence between the surface of saidpressure sensitive adhesive Iand said non-tacky layer.

6. An adhesive structure as set forth in claim 5 wherein said non-tackylayer is a heat activated layer which is convertible to provide saidtacky adhesive surface by the application of heat.

7. An Aadhesive structure as set forth in claim 5 wherein said non-tackylayer is a solvent activated layer which is convertible to provide saidtacky adhesive surface by the application of a solvent.

(References on following page) References Cited UNITED STATES PATENTSMiller 1-61-406 X Moyses 117-6 5 Hartzel 161-167 Wurzburg 161-406 XBennet 161-406 X Bennett 161-406 X 10 Drew 117-80 10 Banks et a1.161-406 X Schram 117-45 Pahl et al. 161-167 Pahl et al. 161-16'7 Reed117-76 EARL M. BERGERT, Primary Examiner.

M. L. KATZ, Assistant Examiner.

Disclaimer 3,343,978.Thomas J. Engelbaoh. Middletown, NJ. ADHESIVETRANS- FERS. Patent dated Se t. 26, 1967. Disclaimer led June 2, 1972,by the assignee, Avery Pro uota Corporation. Hereby enters thisdisclaimer to claims 1-5 and 7 of said patent.

[Ooz'al Gazette J ulg 11, 1.972.]

1. AN ADHESIVE STRUCTURE COMPRISING A FLEXIBLE SUBSTRATE LAYER, A NON-TACKY LAYER, A PRESSURE-SENSITIVE ADHESIVE HAVING A FIRST SIDE IN ADHERING CONTACT WITH SAID SUBSTRATE LAYER AND A SECOND SIDE OPPOSITE SAID FIRST SIDE IN ADHERING CONTACT WITH SAID NON-TACKY LAYER, SAID NON-TACKY LAYER BEING CONVERTIBLE TO A LAYER HAVING A TACKY ADHESIVE SURFACE ON ITS SIDE OPPOSITE SAID PRESSURE-SENSITIVE ADHESIVE, THE ADHESION AT ONE OF SAID SURFACES OF SAID PRESSURESENSITIVE ADHESIVE BETWEEN SAID PRESSURE-SENSITIVE ADHESIVE AND THE ADJACENT ONE OF SAID LAYERS BEING LESS THAN THE ADHESION AT THE OTHER OF SAID SURFACES OF SAID PRESSURESENSITIVE ADHESIVE BETWEEN SAID PRESSURE-SENSITIVE ADHESIVE AND THE OTHER ONE OF SAID LAYERS, SAID PRESSURE-SENSITIVE ADHESIVE SEPARATING ALONG SAID ONE SURFACE THEREOF FROM THE ADHACENT LAYER AND REMAINING WITH SAID OTHER ADJACENT LAYER WHEN SAID LAYERS ARE PULLED APART.
 5. AN ADHESIVE STRUCTURE AS SET FORTH IN CLAIM 1 WHEREIN THE ADHERENCE BETWEEN THE SURFACE OF SAID PRESSURE SENSITIVE ADHESIVE AND SAID SUBSTRATE IS LESS THAN THE ADHERENCE BETWEEN THE SURFACE OF SAID PRESSURE SENSITIVE ADHESIVE AND SAID NON-TACKY LAYER. 